Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
  • H04L1/0056—Systems characterized by the type of code used
  • H04L1/0059—Convolutional codes
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B17/00—Monitoring; Testing
  • H04B17/30—Monitoring; Testing of propagation channels
  • H04B17/309—Measuring or estimating channel quality parameters
  • H04B17/336—Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B17/00—Monitoring; Testing
  • H04B17/30—Monitoring; Testing of propagation channels
  • H04B17/309—Measuring or estimating channel quality parameters
  • H04B17/364—Delay profiles
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
  • H04L1/0006—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission format
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
  • H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
  • H04L1/0041—Arrangements at the transmitter end
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
  • H04L1/0056—Systems characterized by the type of code used
  • H04L1/0064—Concatenated codes
  • H04L1/0066—Parallel concatenated codes
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L27/00—Modulated-carrier systems
  • H04L27/26—Systems using multi-frequency codes
  • H04L27/2601—Multicarrier modulation systems
  • H04L27/2602—Signal structure
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
  • H04L1/0023—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the signalling
  • H04L1/0026—Transmission of channel quality indication

Definitions

• the present invention relates to a multi-carrier communication method and a multi-carrier communication device.
• OFDM Orthogonal Frequency Division Multiplexing
• CDMA Code Division Multiple Access
• the problem is that it cannot be used for multi-carrier communication other than the CDMA method that does not use a spreading chip because it prevents collapse of the signal.
• the technique described in Japanese Patent Application Laid-Open No. 2000-3332724 has a problem of frequency selective fading per spreading chip. It is doubtful that the same effect will be achieved even if they are arranged two-dimensionally in the same way.
• multi-carrier signals are usually subjected to error correction coding such as turbo coding and convolutional coding.
• the arrangement must be considered in units of code blocks generated by the encoding process. Therefore, when arranging code blocks in two dimensions, it is necessary to consider not only the frequency selective fading but also the effects of multipath and fading.
• the error rate characteristics of error correction codes such as turbo codes and convolutional codes are based on the reception quality of code blocks generated by error correction coding processing.
• the likelihood for each bit depends on the quality of each symbol after modulation, that is, the SNR (Signal to Noise Ratio) and the like.
• SNR Signal to Noise Ratio
• FEC error correction
• a 200-bit signal is converted by the FEC coding process. Since the QPSK symbol is generated and transmitted with 2 bits per symbol, 100 symbols of the QPSK symbol are transmitted.
• the transmitted QPSK symbol is received by the receiver via the propagation path, but if the SNR changes for each QPSK symbol, the likelihood changes for every two bits after decoding. Become.
• the FEC performance is degraded due to the data quality variation as described above, even if the average reception quality of the received signal, for example, the SNR has the same value, the SNR variation for each symbol in the code block is large. In this case, there is a problem that the error rate characteristic of the signal after error correction is deteriorated.
• the deterioration of the error rate characteristic due to the variation of the SNR for each symbol in such a code block is a particularly serious problem in a mobile communication system using OFDM signals.
• the SNR fluctuates due to fading in the time axis direction, and frequency selective fading due to multipath occurs in the frequency axis direction. This is because the SNR fluctuates.
• the fluctuation in the time axis becomes larger as the moving speed of the receiver becomes faster, while the fluctuation in the frequency axis becomes larger as the maximum delay time of the multipath signal between the transmitter and the receiver increases. It has the characteristic of becoming larger.
• interference from other cells greatly varies for each subcarrier and for each symbol of the OFDM signal. Therefore, especially in celledges, the SNR of each symbol in one frame of the OFDM signal varies greatly, and the reception performance of the OFDM signal deteriorates. Disclosure of the invention
• An object of the present invention is to improve the error correction rate of a multicarrier signal by arranging a code block generated by error correction coding processing not only in a time axis direction but also in a frequency axis direction. It is an object of the present invention to provide a multi-carrier communication method for adjusting the arrangement in units of code blocks according to the reception state of the multi-carrier communication apparatus and a multi-carrier communication apparatus used in the method.
• a multi-carrier communication method includes: an encoding step of performing an error correction encoding process on a multi-carrier signal; and a transmitting step of transmitting the multi-carrier signal subjected to the error correction encoding process.
• an arrangement adjusting step of adjusting the arrangement of the code blocks generated by the above.
• the reception state is analyzed based on a Doppler frequency and a delay profile of the received multi-carrier signal.
• the reception state is analyzed based on a signal power to interference power ratio for each symbol of the received multicarrier signal.
• a multicarrier communication apparatus includes: an encoding processing unit that performs error correction encoding processing on a multicarrier signal; and an error correction code according to an analysis result of a reception state of the multicarrier signal. Arrangement means for adjusting the arrangement of the code blocks generated by the conversion processing, and transmission means for transmitting the multicarrier signal whose arrangement has been adjusted.
• the multi-carrier communication apparatus preferably includes a plurality of the arrangement adjustment units, and a scheduler for scheduling the plurality of the multi-carrier signals whose arrangement is adjusted.
• Fig. 1A is a diagram showing the relationship between the variation in reception quality of each symbol in the code block and its error rate characteristic.
• FIG.1B is a diagram showing an aspect of the reception quality when the reception quality of each bit in the code block varies greatly
• FIG. 1C is a diagram showing an aspect of the reception quality when the fluctuation of the reception quality for each bit in the code block is small
• FIG. 1D is a diagram showing an aspect of reception quality of additive white Gaussian noise (AW G N: Additive White Gaussian noise).
• AW G N Additive White Gaussian noise
• FIG. 2 is a diagram showing an aspect of one frame of an OFDM signal used in Embodiment 1 of the present invention
• FIG.3A is a diagram showing a mode in which data in one frame of an OFDM signal is arranged in the frequency axis direction when variation in reception quality in the frequency axis direction is small in Embodiment 1 of the present invention.
• FIG. 3B shows that reception quality changes in the time axis direction according to Embodiment 1 of the present invention.
• FIG. 7 is a diagram showing a mode in which data in one frame of an OFDM signal is arranged in the time axis direction when the motion is small.
• FIG.3C is a diagram showing a mode in which data in one frame of an OFDM signal is appropriately arranged according to variation in reception quality in the frequency axis direction and the time axis direction in Embodiment 1 of the present invention.
• FIG. 4A is a diagram showing an example in which a code block is not arranged in a specific subcarrier in one frame in Embodiment 1 of the present invention
• FIG.4B is a diagram showing an example of an arrangement obtained by modifying the form of the code block consisting of 10 symbols in one frame in the first embodiment of the present invention
• FIG. 4C is a diagram showing an arrangement example in which the size (number of symbols) of a code block is appropriately changed according to the characteristics of an error correction code according to Embodiment 1 of the present invention
• FIG. FIG. 13 is a diagram showing an example in which in Embodiment 1, one code block is divided and placed at distant positions, that is, two code blocks of 5 symbols are placed apart from each other.
• FIG.4E is a diagram showing an example in which, when the same OFDM signal is transmitted to a plurality of receivers in Embodiment 1 of the present invention, code blocks are arranged according to the reception state of each receiver. ,
• FIG.4F shows an example of arrangement in which, when transmitting the same OFDM signal to two receivers in Embodiment 1 of the present invention, 50 symbols are dispersed in one frame and assigned to each receiver.
• FIG. 5 is a diagram showing an example of arrangement of code blocks in one frame of an OFDM signal when there are a plurality of receivers used in Embodiment 1 of the present invention.
• FIG. 6 is a block diagram showing configurations of a transmitter and a receiver used in Embodiment 1 of the present invention.
• FIG. 7 is a diagram showing an example of a format table referred to when determining the arrangement of code blocks in the first embodiment of the present invention.
• FIG. 8 is a block diagram showing a configuration of a receiver used in Embodiment 2 of the present invention.
• FIG. 9 is a block diagram showing a configuration of a transmitter and a receiver used in Embodiment 3 of the present invention.
• FIG. 10 is a block diagram showing a configuration of a transmitter and a receiver used in Embodiment 4 of the present invention.
• the gist of the present invention is that the analysis result of the reception state of the multicarrier signal is fed back to the transmitter, and the reception state of the same code block generated by the error correction coding process of the multicarrier signal becomes uniform.
• the reception state of the same code block generated by the error correction coding process of the multicarrier signal becomes uniform.
• it is arranged not only in the time axis direction but also in the frequency axis direction.
• Fig. 2 shows an OFDM signal in which one frame has a total of 100 symbols of 10 symbols in the time axis direction and 10 symbols in the frequency axis direction.
• Embodiment 1 will be specifically described below, taking as an example the case of transmitting and receiving OFDM signals using the 100 symbols as one frame.
• a code block generated by performing error correction coding on an OFDM signal is composed of 10 symbols
• 10 code blocks can be arranged in one frame.
• the SNR fluctuation (reception state) of each symbol in one frame is measured by observing the Doppler frequency and the delay profile. Analyze and adjust the placement of code blocks in one frame of the OFDM signal transmitted thereafter based on the analysis results By doing so, the fluctuation of the SNR for each symbol in the code block is reduced.
• the code blocks may be arranged in a form of 5 symbols in the time axis direction where the movement is small, and 2 symbols in the frequency axis direction where the fluctuation of the SNR is large.
• the arrangement of the code blocks in one frame of the OFDM signal is appropriately adjusted such that the actual reception state of the OFDM signal is analyzed and the SNR variation between symbols in the code block is reduced according to the analysis result. do it.
• the following is an example of the arrangement of code blocks in one frame.
• FIG. 4A shows an example in which no code block is allocated to a specific subcarrier in one frame.
• FIG. 4B shows an example of an arrangement in which the form of a code block composed of 1 ° symbols in one frame is modified. For example, as shown in the frequency axis direction and the time axis direction, each code block consisting of 10 symbol x 1 symbol, 5 symbol x 2 symbol, and 2 symbol x 5 symbol may be mixed. According to this arrangement example, it is possible to adapt even if the amount of variation in the SNR for each symbol in one frame changes locally.
• FIG. 4C shows an arrangement example in which the size (number of symbols) of a code block is appropriately changed according to the characteristics of the error correction code. Since the error correction rate of a turbo code or the like increases as the number of symbols of the code block increases, the code block may be increased as long as it can be arranged in one frame. In FIG. 4C, seven code blocks of 10 symbols and one code block of 30 symbols are mixed.
• FIG. 4D shows an example in which one code block is divided and separated, that is, two code blocks each including 5 symbols are separated and arranged (see the hatched portion in FIG. 4D). According to this arrangement example, it is possible to adaptively cope with a case where a portion where the reception state is approximated appears separately in one frame.
• FIG. 4E shows an example where, when transmitting the same OFDM signal to a plurality of receivers, code blocks are arranged according to the reception state of each receiver. According to this arrangement example, it is possible to arrange code blocks according to the reception state of each receiver, and it is possible to improve the error rate characteristics of all receivers.
• FIG. 4F shows an example of arrangement in which 50 symbols are dispersed and assigned to each receiver in one frame when the same OFDM signal is transmitted to two receivers. According to this arrangement example, it is only necessary to appropriately select 50 symbols having an approximate SNR value in one frame, and configure a code block with the selected 50 symbols. Accordingly, it is possible to improve the error rate characteristics of all receivers.
• FIG. 4E shows an example where, when transmitting the same OFDM signal to a plurality of receivers, code blocks are arranged according to the reception state of each receiver. According to this arrangement example, it is possible to arrange code blocks according to the reception state of each receiver, and it is possible to improve the error rate characteristics of all receivers.
• a receiver 1 is a mobile communication terminal device that moves at a high speed and is in a receiving state where the influence of multipath is small.
• the receiver 2 is a mobile communication terminal device that moves at a low speed and is in a receiving state that is greatly affected by multipath.
• the receiver 3 is a mobile communication terminal device that moves at a medium speed, and is in a medium reception state with the influence of multipath.
• code blocks are arranged in one frame in accordance with the reception state of each of these receivers, it is preferable that code blocks are arranged continuously in the frequency axis direction for receiver 1, and receiver 2 is preferably arranged for It is preferable that code blocks are arranged continuously in the time axis direction.
• code blocks are continuously arranged for 5 symbols in the time axis direction and continuously for 2 symbols in the frequency axis direction. The mode of arrangement is preferable.
• One frame of OFDM signal can be generated by frequency division multiplexing (FDMA) of the code blocks arranged for each of these three receivers. Note that the OFDM signal generated in this way is composed of 10 symbols in the time axis direction and 30 symbols in the frequency axis direction, for a total of 300 symbols, as one frame.
• FDMA frequency division multiplexing
• FIG. 6 is a block diagram showing a configuration of a transmitter (a) and a receiver (b) used in one-to-one OFDM communication.
• the transmitter 500 includes a block division section 501, an error correction coding section 502, a code block arrangement section 503, an OFDM transmission processing section 504, a transmission radio frequency (RF) section 505, It comprises a reception RF section 506, a request format detection section 507, a frame format determination section 508, and an antenna element 509.
• the receiver 550 includes a reception RF section 551, an OFDM reception processing section 552, a code block rearrangement section 553, an error correction decoding section 554, and a maximum Doppler frequency detection section 55.
• Time axis fluctuation prediction value calculation section 5 56 Time axis fluctuation prediction value calculation section 5 56, delay profile detection section 5 57, frequency axis fluctuation prediction value calculation section 5 58, fluctuation amount comparison section 5 59, request format determination section 5 6 0 , A required format transmitting section 561, a transmitting RF section 562, and an antenna element 563.
• the transmission data is divided into a predetermined size corresponding to a code block by the block division unit 501 in accordance with an instruction from the frame format determination unit 508.
• the individual transmission data divided by the block division unit 501 is input to an error correction encoding unit 502, where it is subjected to error correction encoding processing such as convolutional encoding and processed into a code block.
• This code block is input to a code block arranging section 503, where the arrangement is instructed by the frame format determining section 508, that is, the arrangement specified in one frame after being converted into an OFDM signal. It is rearranged to become.
• the code block input from the code block arrangement unit 503 to the OFDM transmission processing unit 504 is subjected to serial-parallel conversion, IFFT (inverse fast Fourier transform), parallel-serial conversion, and guard interval by the OFDM transmission processing unit 504.
• serial-parallel conversion IFFT (inverse fast Fourier transform)
• parallel-serial conversion parallel-serial conversion
• guard interval by the OFDM transmission processing unit 504.
• a known process for generating an OFDM signal such as an input signal is performed.
• the OFDM signal input from the OFDM transmission processing unit 504 to the transmission RF unit 505 is subjected to signal processing such as digital / analog (DZA) conversion, carrier multiplication, amplification, and the like. It is transmitted wirelessly from 509.
• DZA digital / analog
• the OFDM signal transmitted from transmitter 500 is received by antenna element 563 of receiver 550 via the propagation path.
• the OFDM signal received by the antenna element 563 is input to the reception RF section 551, where signal processing such as amplification, frequency conversion, and analog-to-digital (A / D) conversion is performed.
• the OFDM signal input from the reception RF section 551 to the OFDM reception processing section 552 is subjected to signal processing such as serial-parallel conversion, FFT processing, and parallel-serial conversion, and then code block arrangement.
• the switching section 553, the maximum Doppler frequency detection section 555, and the delay profile detection section 557 are respectively input.
• the code blocks included for each frame are rearranged by the code block arranging section 503. It is returned to its original configuration before being replaced.
• the code blocks extracted by being rearranged to the original arrangement are decoded by a known decoding algorithm such as a Viterbi algorithm in an error correction decoding section 554, decoded, and sequentially output.
• the OFDM signal is measured by a maximum Doppler frequency detection unit 555 in which the Doppler frequency for each symbol is measured for each frame. Then, the maximum Doppler frequency measured for each symbol is input to the time axis direction fluctuation predicted value calculation section 556, where the fluctuation amount of one frame in the time axis direction is calculated. Further, the time axis direction fluctuation predicted value calculation section 556 predicts the fluctuation amount in the time axis direction of the subsequently received OFDM signal based on the calculated change of the fluctuation amount in the time axis direction. You. The fluctuation amount prediction value in the time axis direction is input to the fluctuation amount comparing section 559.
• the delay profile detection unit 557 averages the delay time and signal strength of the input OFDM signal for each symbol for each frame, and calculates the distribution of each symbol with respect to the average value. A delay profile is generated for each symbol. This delay profile is input to the frequency-axis direction fluctuation prediction value calculation unit 558, where the OFDM signal received thereafter based on the change of the fluctuation amount in the frequency axis direction of one frame of the OFDM signal is input. Is estimated in the frequency axis direction. Then, the fluctuation amount prediction value in the frequency axis direction is input to the fluctuation amount comparison unit 559.
• the fluctuation amount comparison unit 559 includes a time axis direction fluctuation amount prediction value for the maximum Doppler frequency input from the time axis direction fluctuation prediction value calculation unit 556, and a frequency axis direction fluctuation prediction value calculation unit 5 5 Is compared with the predicted value of the fluctuation amount in the frequency axis direction for the delay profile input from 8, and the SNR of each symbol in the time axis direction of one frame of the OFDM signal received thereafter is compared. The ratio between the degree of variation and the degree of variation in the same frequency axis direction is calculated. The calculated SNR variation ratio of each symbol in one frame of the OFDM signal is input to the required format determination unit 560.
• the request format determination unit 560 determines the arrangement of the code blocks that minimizes the variation of the SNR for each symbol in the code block, taking into account one frame of the OFDM signal comprehensively, according to the variation ratio. You.
• the arrangement of such code blocks is based on a trial-and-error combination of the form of one code block described in the format tables A and B shown in Fig. 7, for example, and performs comprehensive evaluation in one frame each time. Can be determined by FIG. 7 will be described later.
• the format of the code block arrangement in one frame of the OFDM signal determined by the request format determination unit 560 is a known format while passing through the request format transmission unit 561 and the transmission RF unit 562. After signal processing, the signal is wirelessly transmitted from antenna element 563.
• the signal wirelessly transmitted from the receiver 550 is received by the antenna element 509 of the transmitter 550, the signal is amplified by the reception RF section 506, and the signal is subjected to frequency conversion and AZD conversion. Signal processing is performed. Then, this transmission signal is input to the request format detection section 507, where the contents of the format are extracted. Further, the extracted format is input to the frame format determining unit 508, where the size of the code block and the arrangement of the code blocks in one frame are specifically determined.
• the frame format determination unit 508 sends an instruction to the block division unit 501 about the size (number of symbols) of one code block, and the code block arrangement unit 503 An instruction on the arrangement of code blocks in one frame of the OFDM signal is input to each OFDM signal. After that, each of the above-described signal processing is repeatedly performed in each of the above components.
• FIG. 7 shows an example of the form of one code block that can be used to generate a format for the arrangement of code blocks in one frame of an FDM signal, which is determined by the request format determination section 560. Show.
• the format table A shows an example of a form of a code block composed of 10 symbols.
• (T, f)” in the table means “(the number of symbols in the time axis direction, the number of symbols in the frequency axis direction)”.
• the format table B shows an example of the form of these code blocks in the case where a code block composed of 10 symbol and a code block composed of 20 symbol are mixed.
• the request format determination unit 560 uses the format table A or the format table B to appropriately combine these code blocks according to the reception state of the OFDM signal, and arrange the code blocks in one frame. Can be determined.
• the receiver 550 analyzes the reception state of the OFDM signal based on the maximum Doppler frequency and the delay profile. Therefore, it is possible to separately analyze the adverse effects of the multicarrier signal in the frequency axis direction and the time axis direction of the multicarrier signal caused by passing through the propagation path. It is possible to precisely adjust the arrangement of the code packages in the frame.
• FIG. 8 is a block diagram showing a configuration of a receiver used in the multicarrier communication method according to the second embodiment.
• the receiver calculates the amount of SNR variation for each symbol in the code block of the FDM signal by using its SIR (Signal-to-Interference power Ratio). Based on the power ratio), the arrangement of code blocks is determined.
• SIR Signal-to-Interference power Ratio
• the receiver 750 is the same as the receiver 550, except that the maximum Doppler frequency detector 555, the time-axis fluctuation prediction value calculator 556, the delay profile detector 557, the frequency axis fluctuation prediction value is calculated. Instead of the unit 558 and the variation comparison unit 559, the received SIR prediction unit for each symbol 701, 1X10 SIR variance calculation unit at the time of mapping 702, SIR variance calculation unit at the time of 5X2 mapping It is provided with a SIR variance calculation unit 704 and an SIR variance value comparison unit 705 at the time of 703, 10 X 1 matching.
• these three SIR variance calculation units 720, 703, and 704 include a rearrangement unit 721, an average SIR calculation unit for each code block 722, and an SIR variance calculation unit for each code block 72. 3 and SIR variance averaging section 7 2 4 respectively.
• the OFDM signal output from the OFDM reception processing section 552 is accumulated for one frame, and the SIR is measured for all symbols included therein. Then, when the SIR for all the symbols obtained by the measurement is 1 ⁇ 10 mapping, the SIR variance calculation unit 702, when mapping 5 ⁇ 2, the SIR variance calculation unit 703 and when the 10 ⁇ 1 mapping SIR variance calculation Input to the sections 704 respectively.
• the SIR variance calculator 702 inputs the input SIR for each symbol to the rearranger 721.
• the code blocks are arranged as shown in FIG. 3A. According to this assumption, after the SIR for each symbol is divided for each code block, this code block
• the SIR for each code block is sequentially input in parallel to the code block average SIR calculation section 722 and the code block per SIR variance calculation section 723.
• the average SIR calculator for each code block 722 calculates the average of the SIR for each code block.
• this average SIR is calculated by the SIR variance calculation unit for each code block 7 2 3 Is input to The per-code-block SIR variance calculator 723 calculates the variance for each code block based on the input average SIR and the SIR of each symbol in the code block corresponding to the average SIR.
• the SIR variance for each code block is input to the SIR variance averaging unit 724, where the SIR variance for each code block for one frame is accumulated and averaged.
• the averaged SIR variance for each code block for one frame is sequentially input to the SIR variance value comparison unit 705 as an SIR variance value.
• the signal processing similar to the signal processing in the SIR variance calculation unit at the time of this 1 ⁇ 10 mapping is performed by the SIR variance calculation unit at the time of 5 ⁇ 2 mapping and the SIR variance calculation unit at the time of mapping.
• the SIR variance value is input to the SIR variance value comparison unit 705.
• the SIR variance comparison unit 705 the SIR variance calculation unit 702 at the time of 1 ⁇ 10 rubbing, the SIR variance calculation unit 702 at the time of 5 ⁇ 2 rubbing, and the SIR variance calculation unit at the time of 10 ⁇ 1 mapping
• the SIR variance values input from 04 are compared with each other, and the arrangement of code blocks in one frame is selected so that the SIR variance value is minimized.
• the arrangement of the selected code blocks is notified to the request format determination unit 560, and then the format of the arrangement of the code blocks is wirelessly transmitted to the transmitter 500 as in the first embodiment.
• the reception state of a multicarrier signal is analyzed based on the SIR for each symbol, so that the reception state can be analyzed in detail.
• the error correction rate of the multicarrier signal can be reliably increased.
• the three SIR variance calculators 72, 703, and 704 are assumed on the assumption that a code block composed of 10 symbols is arranged in one frame of the FDM signal.
• the present invention is not limited to this case. For example, if multiple code blocks can be contained in one frame of an OFDM signal, the size of the code block Or the form may be changed, or the number of SIR distributed calculation units may be increased.
• FIG. 9 is a block diagram showing a configuration of a multicarrier communication apparatus according to Embodiment 3.
• the receiver in one-to-one OFDM communication, the receiver does not analyze the reception state of the OFDM signal, transmits information on the reception state to the transmitter, and the transmitter performs the operation based on the information.
• the arrangement of code blocks in one frame of the OFDM signal is determined.
• the transmitter 800 includes a channel information detector 807 instead of the request format detector 507 in the transmitter 500.
• the channel information detection unit 807 analyzes the reception state of the OFDM signal transmitted from the receiver 850 based on the following information on the reception state, thereby arranging the code blocks in one frame of the OFDM signal. To determine.
• the information on the reception state of this OFDM signal includes the maximum Doppler frequency, delay profile, maximum delay time, the number of delayed waves, the delay time of each path and the power of each path, and the channel estimation value for each subcarrier. is there.
• the receiver 850 has the same configuration as the receiver 550, except that the predicted time axis fluctuation value calculation section 556, the predicted frequency axis fluctuation value calculation section 558, the fluctuation amount comparison section 559, and the required format.
• a channel information generating unit 859 and a channel information transmitting unit 861 are provided instead of the determining unit 5600 and the request format transmitting unit 561.
• Channel information generating section 859 and channel information transmitting section 861 generate the above-mentioned information on the reception state of the FDM signal, and transmit these pieces of information to transmitter 800 by radio.
• the multicarrier communication method and the communication device it is possible to separately analyze the adverse effect of the multicarrier signal on the frequency axis and the adverse effect on the time axis caused by passing through the propagation path. Based on these analysis results, the arrangement of code blocks in one frame of the multicarrier signal can be finely adjusted, and the load of signal processing on the receiver can be reduced. Therefore, the configuration of the receiver can be simplified, and the receiver can be made lighter and smaller.
• FIG. 10 is a block diagram showing a configuration of a multicarrier communication apparatus according to Embodiment 4.
• a plurality of receivers simultaneously perform OFDM communication with one transmitter.
• the transmitter 900 has an OFDM transmission processing section 504, a transmission RF section 505, a reception RF section 506, an antenna element 509, a scheduler 923, a multiplexing section 922, and a plurality of code blocks. And a conversion unit 920. Also, the code block unit 920 includes a block division unit 501, an error correction coding unit 502, a code block arrangement unit 503, a request format detection unit 507, and a frame format determination unit 50. 8. Equipped with the same number as the number of receivers that are equipped with the separation unit 921 and the SIR information acquisition unit 922, and perform communication at the same time.
• the receiver 950 further includes, in addition to the components included in the receiver 550, a reception SIR detection section 971, a reception SIR information transmission section 972, and a multiplexing section 973.
• the OFDM signal is input from the OFDM reception processing section 552 to the reception SIR detection section 971.
• the reception SIR detection section 971 accumulates SIRs of all symbols in one frame of the OFDM signal.
• the SIR of the symbol for one frame that has been input is input to the reception SIR information transmission unit 972, where it is averaged in units of one frame.
• This average SIR is input to the multiplexing unit 973, where it is multiplexed with the format for the arrangement of the code blocks input from the request-formatted transmitting unit 561, and then transmitted to the transmitter 900. Sent.
• the signal wirelessly transmitted from the receiver 950 is received by the transmitter 900, and then is input to the separation unit 921 of the code blocking unit 920.
• the demultiplexing unit 921 determines whether or not the input signal should be processed in the included code blocking unit 920, and only when a determination result indicating that the signal should be processed is obtained, the Are separated and extracted from the average SIR and the format for the arrangement of the code packs included in the data. Then, the average SIR is input to the SIR information acquisition unit 922, while the format for the arrangement of code blocks is input to the request format detection unit 507.
• the SIR information acquisition unit 9222 acquires information on the reception state of the OFDM signal in the receiver 9550 based on the input average SIR.
• the scheduler 923 determines the number of symbols to be assigned to each receiver 950 and the arrangement of code blocks for the next transmission of the OFDM signal based on the information on the reception status of each receiver 950. Is done. This determination in the scheduler 923 is input to the multiplexing unit 924, and is realized by performing desired signal processing here.
• a plurality of code blocking units 920 corresponding to the arrangement adjusting means are provided, and a scheduler is provided for appropriately selecting and combining outputs from these units. Therefore, when transmitting a multi-carrier signal to multiple receivers, the overall error correction rate increases in consideration of the reception status of all receivers. Thus, the arrangement of the code blocks in the multi-carrier signal can be adjusted.
• a multi-level modulation scheme may be adopted, and in that case, the code blocks may be arranged by dividing the group into upper bits and lower bits.
• the actual reception state of a multicarrier signal is analyzed, and the arrangement of code blocks is appropriately adjusted according to the analysis result.
• the error correction rate of the multi-carrier signal can be reliably improved by adaptively responding to the adverse effect from the signal.
• the Doppler frequency and the delay profile are simultaneously observed, it is possible to separately analyze the adverse effect in the frequency axis direction and the adverse effect in the time axis direction caused by passing through the propagation path.
• the arrangement of the code blocks can be finely adjusted based on the analysis results.
• the reception state of a multicarrier signal is analyzed based on the SIR for each symbol, a more precise analysis result can be obtained, and the error correction rate of the multicarrier signal can be reliably increased. .
• a scheduler which appropriately selects and combines outputs from a plurality of arrangement adjusting means, when transmitting a multi-carrier signal to a plurality of receivers, all the receivers are used. In consideration of this, it is possible to adjust the arrangement of the code blocks in the multi-carrier signal so that the error correction rate is increased comprehensively.
• the present invention the actual reception state of a multicarrier signal is analyzed, and the arrangement of code blocks is appropriately adjusted in accordance with the analysis result. Therefore, the present invention is adaptive to the adverse effect from the ever-changing propagation path. Accordingly, the error correction rate of the multicarrier signal can be reliably improved.
• the present invention can be applied to a multi-carrier transmitting device and a multi-carrier receiving device mounted on a mobile station device, a base station device, and the like in a mobile communication system.

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